A particular type of inflatable vehicle occupant protection device is commonly referred to as an air bag. The air bag is stored in a vehicle in a folded, uninflated condition at a location adjacent to the vehicle occupant compartment. When the vehicle experiences a crash, inflation fluid is directed to flow from an inflator into the air bag. The inflation fluid unfolds and inflates the air bag from the stored condition to a deployed condition in which the air bag
When the air bag extends into the vehicle occupant compartment, it can engage an occupant of the vehicle to help protect the occupant from a forceful impact with parts of the vehicle. The manner in which the air bag engages the occupant is determined in part by the configuration imparted to the air bag by the inflation fluid as the inflation fluid unfolds and deploys the air bag into the vehicle occupant compartment.